According to The Asahi Shimbun, a major Japanese general contractor, Taisei Corp, said it has created a three-story building that supplies all of its energy needs through solar power and significantly cuts down on wasted electricity.Taisei intends to lower the cost of the construction method and commercialize it by 2020.According to Taisei officials, the company spent an entire year examining whether the building at its technology center in Yokohama, Japan could operate without receiving outside power.Taisei applied a thin coating for photovoltaic power generation to half of the surface of the exterior walls and set up solar panels on the roof.After the one-year study, Taisei found that solar power alone could cover all the electricity used at the building.In addition, the amount of electricity used inside the facility was lowered by 75 percent through various measures, such as introducing lighting devices that illuminate only around people and installing air-conditioning systems that use circulating water.The cost to build such a self-sufficient facility is 1.5 to two times higher than the price to construct a similar-sized building powered by outside electricity sources.But Taisei said consumers will prefer the power-saving building if the construction cost is lowered to 1.2 times the expense for normal buildings.